Cancer cells dupe the body’s immune system

Cancers may be wounds that never heal, suggest the first live images of tumours forming.

It seems individual cancer cells send out the same distress signals as wounds, tricking immune cells into helping them grow into tumours. The finding suggests that anti-inflammatory drugs could help to combat or prevent cancer.

“Lifelong, if you take a small quantity of something that suppresses inflammation, such as aspirin, it could reduce the risk of cancer,” says Adam Hurlstone of the University of Manchester, UK.

When tissue is wounded or infected it produces hydrogen peroxide. White blood cells called leukocytes are among the first cells to react to this trigger, homing in to kill the infectious agent, clean up the mess and rebuild damaged tissue. At first, the tissue becomes inflamed, but this subsides as the wound is cleared and rebuilding continues.

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Now, a study in zebra fish shows that this process is also instigated and sustained by tumour cells.

Hurlstone and colleagues genetically engineered zebra fish so that skin cells and leukocytes would glow different colours under ultraviolet light. Some zebra fish were also engineered to have cancerous skin cells.

The team found that the cancerous skin cells secreted hydrogen peroxide, summoning leukocytes which helped them on their way to becoming a tumour. When the team blocked hydrogen peroxide production in the zebra fish, the leukocytes were no longer attracted to cancerous cells and the cancer colonies reduced in number.

More alarmingly, the researchers found that healthy skin cells adjacent to the cancerous ones also produced hydrogen peroxide, suggesting that cancer cells somehow co-opt them into triggering inflammation.